I had to fire General Flynn because he lied to the Vice President and the FBI. He has pled guilty to those lies. It is a shame because his actions during the transition were lawful. There was nothing to hide!

The charging documents against Mr Flynn state that he was directed to make contact with Russian officials by a “very senior member” of the Trump transition team.

Several US news organisations say the very senior official now under the spotlight is Jared Kushner – Mr Trump’s adviser and son-in-law.

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Media captionAfter Flynn’s guilty plea, what next for the Russia investigation?

US intelligence agencies say Russia’s President Vladimir Putin directed a state effort to influence the US election in favour of Mr Trump.

Mr Trump has repeatedly denied that his campaign or transition team colluded in Russian actions. Speaking to reporters on Saturday, he said: “What has been shown is no collusion, no collusion. There has been absolutely no collusion. So we’re very happy.”

What are the charges?

Mr Flynn was forced to resign in February, just 23 days into his job. He was questioned by the FBI for misleading the White House about meeting then-Russian ambassador Sergei Kislyak during the transition period, before Mr Trump took office.

The two reportedly discussed Russia’s response to US sanctions, at the direction of the Trump team.

falsely telling FBI agents that on or about 29 December 2016 he did not ask Mr Kislyak to “refrain from escalating the situation in response to sanctions that the United States had imposed against Russia that same day”

failing to recall that Mr Kislyak had later told him Russia was moderating its response to the sanctions as a result of his request

falsely saying that, on or about 22 December 2016, he did not ask Mr Kislyak to “delay the vote on or defeat a pending United Nations Security Council resolution”. The discussion came a day before the Obama administration decided not to veto a resolution asserting that Israeli settlements on occupied Palestinian territory “had no legal validity”

making false statements about the Turkish government’s involvement and supervision of a project that his intelligence company was taking part in.

The charge of making false statements normally carries up to five years in prison, but under the terms of his plea deal Mr Flynn faces a lighter sentence of only up to six months, court filings show.

White House lawyer Ty Cobb said: “Nothing about the guilty plea or the charge implicates anyone other than Mr Flynn.”

The administration has attempted to distance itself from Mr Flynn, who previously served in the Obama administration before being fired. Mr Obama reportedly advised his successor not to hire the former general, but Mr Trump appointed him to one of the most senior positions in the country.

Mr Cobb described Mr Flynn as a “former Obama administration official” who was “at the White House for 25 days”.

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Media captionHow Michael Flynn became entangled in Russia probe

Mr Flynn is not the first former Trump official to be charged.

In October, Mr Trump’s former campaign manager, Paul Manafort, and his business associate Rick Gates were accused of conspiring to defraud the US in dealings with Ukraine (both deny the charges). Another ex-aide, George Papadopoulos, has also pleaded guilty to making false statements to FBI agents

Tax bill victory

The tax reform bill passed on Friday, amid the Russia investigation developments, sees a sharp cut in corporation tax and has been fiercely criticised by Democrats and others as a bill designed to benefit America’s richest citizens.

The vote will be seen as a major victory for Mr Trump, who has failed to get major legislative movement in Congress, despite Republicans controlling both houses.

The president said he wants the measures enacted by the end of the year and he congratulated Republicans for taking the US “one step closer to delivering massive tax cuts for working families”.

The Senate will now have to merge its legislation with that passed last month by the House of Representatives, before it can be signed into law by the president.